1. Field of the Invention
The present invention relates to a novel photoconductive film and an electrophotoconductive member with high and panchromatic sensitivity utilizing such a film.
2. Description of the Prior Art
Up to now a great number of reports have been presented on photoconductive pigments or dyes.
For instance, "RCA Review", Vol. 23, pp. 413-419 (1962.9) describes photoconductivity of phthalocyanine pigments, and electrophotographic photosensitive members utilizing these pitments are disclosed in U.S. Pat. Nos. 3,397,086 and 3,816,118. Besides these, the following pigments and dyes, for example, are disclosed as organic semiconductors for use in electrophotographic photosensitive members. That is; pyrylium dyes as disclosed in U.S. Pat. Nos. 4,315,983 and 4,327,169 and "Research Disclosure" 20517 (1981.5); squaric acid methine dyes as disclosed in U.S. Pat. No. 3,824,099; and dis-azo pigments as disclosed in U.S. Pat. Nos. 3,898,084 and 4,251,613.
These organic semiconductors have advantages over inorganic ones in that the former is easy to synthesize and from the former a compound having a desired spectral sensitivity can be chosen, and in that electrophotographic photosensitive members provided with films of such organic semiconductors on conductive substrates exhibit improved color sensitivity. However, the hitherto found organic semiconductors are not much satisfactory in sensitivity and panchromatic property. In particular, existing organic and inorganic semiconductors are sensitive only to rays of shorter wavelengths (e.g. 350-500 nm), rays of longer wavelengths (e.g. 600-750 nm), or rays of intermediate wavelentgths (e.g. 500-600 nm); that is, no panchromatic semiconductor has been found out that exhibits sensitivity throughout the whole region ranging from the shorter wavelength region to the longer wavelength region.
Accordingly electrophotographic photosensitive members hitherto used in color copying machines have been supplied with panchromatic sensitivity by incorporating, for example, a blue, green, or red sensitizer into the photosensitive layer. Such photosensitive members, however, have drawbacks in that the sensitizer is faded by light irradiation in the image exposure and in the charge elimination or static-image erasing and this causes the disappearance of the desired panchromatic sensitivity during a long term service, and in particular few red sensitizers show good properties. Thus no photosensitive member satisfactory in panchromatic property has been obtained.